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Backflow preventer

pageyjimpageyjim Member Posts: 5
edited November 2018 in Gas Heating
Is it best practice to install one with an an atmospheric vent on a hot water boiler feed? If so what are the advantages? Thanks in advance.

Comments

  • hot_rodhot_rod Member Posts: 11,990
    pageyjim said:

    Is it best practice to install one with an an atmospheric vent on a hot water boiler feed? If so what are the advantages? Thanks in advance.

    The code requirements or local code official requirements vary widely on appropriate type. Some areas are not requiring testable type of BFDs on boilers even with tap water fill. Best check with the code officials if that applies inn your area.

    Here are examples of the two most common.

    Dual check with vent, and testable RPZ type.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • pageyjimpageyjim Member Posts: 5
    hot rod_7 said:

    pageyjim said:

    Is it best practice to install one with an an atmospheric vent on a hot water boiler feed? If so what are the advantages? Thanks in advance.

    The code requirements or local code official requirements vary widely on appropriate type. Some areas are not requiring testable type of BFDs on boilers even with tap water fill. Best check with the code officials if that applies inn your area.

    Here are examples of the two most common.

    Dual check with vent, and testable RPZ type.
    Thanks for the response It doesn't have to be able to be tested in my residential application. I wanted to know more about the atmospheric venting and the pluses and minuses of that.
  • kevinj_4kevinj_4 Member Posts: 83
    pageyjim said:

    hot rod_7 said:

    pageyjim said:

    Is it best practice to install one with an an atmospheric vent on a hot water boiler feed? If so what are the advantages? Thanks in advance.

    The code requirements or local code official requirements vary widely on appropriate type. Some areas are not requiring testable type of BFDs on boilers even with tap water fill. Best check with the code officials if that applies inn your area.

    Here are examples of the two most common.

    Dual check with vent, and testable RPZ type.
    Thanks for the response It doesn't have to be able to be tested in my residential application. I wanted to know more about the atmospheric venting and the pluses and minuses of that.
    So far as I know backflow preventers vent.

    Check valves do not vent.

    Have you got a pic or model of the unvented type?

    I would think the minimum would be a 9D.
  • hot_rodhot_rod Member Posts: 11,990
    Depends on the level of hazard. A dual check without vent port is usually considered acceptable only for non health hazard applications.

    So the question becomes is boiler water considered a health hazard? Plain tap water would not be, but if any glycols were added or could be added the hazard level changes and a higher levels of protection is required by codes.

    Then vent port gives a visual that a back flow condition has occurred.

    The vent ports will from time to time spit some water. This is not necessarily a sign of a failed BFD but basically the device doing it's job reacting to a reduced pressure condition.

    I highly recommend the vents port have a discharge tube to the floor or near a drain.

    Oddly enough across some state different AHJ insist on different level of protection, so that become a challenge for installers and service techs.

    Boilers inspectors and AHJs are more concerned about what could happen in the future, suppose a serviceperson adds a cleaner to the boiler, or a conditioner fluid, the potential to contaminate a public water systems has more jurisdictions insisting on higher protection level devices.

    If it has test ports it needs to be tested and certified yearly to maintain that listing. This adds cost to the homeowner.

    We have a great webinar lined up on this topic in December, here is a link if any want to learn more about BFD from a master plumber, back flow test trainer and Milwaukee inspector.

    https://www.caleffi.com/usa/en-us/coffee-caleffitm-schedule
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • pageyjimpageyjim Member Posts: 5
    For some reason I thought this one did not vent and I see now that it does. And that was the reason for my question. Thanks to all who answered.
    https://www.supplyhouse.com/Watts-0063190-BBFP-1-2-IPS-Backflow-Preventer
  • kevinj_4kevinj_4 Member Posts: 83
    pageyjim said:

    For some reason I thought this one did not vent and I see now that it does. And that was the reason for my question. Thanks to all who answered.
    https://www.supplyhouse.com/Watts-0063190-BBFP-1-2-IPS-Backflow-Preventer

    That looks a lot like the old 9d, backflow without test ports.

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